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DIG(1)                               BIND9                              DIG(1)

NAME
       dig - DNS lookup utility

SYNOPSIS
       dig [@server] [-b address] [-c class] [-f filename] [-k filename]
           [-p port#] [-t type] [-x addr] [-y name:key] [-4] [-6] [name]
           [type] [class] [queryopt...]

       dig [-h]

       dig [global-queryopt...] [query...]

DESCRIPTION
       dig (domain information groper) is a flexible tool for interrogating
       DNS name servers. It performs DNS lookups and displays the answers that
       are returned from the name server(s) that were queried. Most DNS
       administrators use dig to troubleshoot DNS problems because of its
       flexibility, ease of use and clarity of output. Other lookup tools tend
       to have less functionality than dig.

       Although dig is normally used with command-line arguments, it also has
       a batch mode of operation for reading lookup requests from a file. A
       brief summary of its command-line arguments and options is printed when
       the -h option is given. Unlike earlier versions, the BIND9
       implementation of dig allows multiple lookups to be issued from the
       command line.

       Unless it is told to query a specific name server, dig will try each of
       the servers listed in /etc/resolv.conf.

       When no command line arguments or options are given, will perform an NS
       query for "." (the root).

       It is possible to set per-user defaults for dig via ${HOME}/.digrc.
       This file is read and any options in it are applied before the command
       line arguments.

SIMPLE USAGE
       A typical invocation of dig looks like:

           dig @server name type

       where:

       server
          is the name or IP address of the name server to query. This can be
          an IPv4 address in dotted-decimal notation or an IPv6 address in
          colon-delimited notation. When the supplied server argument is a
          hostname, dig resolves that name before querying that name server.
          If no server argument is provided, dig consults /etc/resolv.conf and
          queries the name servers listed there. The reply from the name
          server that responds is displayed.

       name
          is the name of the resource record that is to be looked up.

       type
          indicates what type of query is required -- ANY, A, MX, SIG, etc.
          type can be any valid query type. If no type argument is supplied,
          dig will perform a lookup for an A record.

OPTIONS
       The -b option sets the source IP address of the query to address. This
       must be a valid address on one of the host's network interfaces or
       "0.0.0.0" or "::". An optional port may be specified by appending
       "#<port>"

       The default query class (IN for internet) is overridden by the -c
       option.  class is any valid class, such as HS for Hesiod records or CH
       for CHAOSNET records.

       The -f option makes dig operate in batch mode by reading a list of
       lookup requests to process from the file filename. The file contains a
       number of queries, one per line. Each entry in the file should be
       organised in the same way they would be presented as queries to dig
       using the command-line interface.

       If a non-standard port number is to be queried, the -p option is used.
       port# is the port number that dig will send its queries instead of the
       standard DNS port number 53. This option would be used to test a name
       server that has been configured to listen for queries on a non-standard
       port number.

       The -4 option forces dig to only use IPv4 query transport. The -6
       option forces dig to only use IPv6 query transport.

       The -t option sets the query type to type. It can be any valid query
       type which is supported in BIND9. The default query type "A", unless
       the -x option is supplied to indicate a reverse lookup. A zone transfer
       can be requested by specifying a type of AXFR. When an incremental zone
       transfer (IXFR) is required, type is set to ixfr=N. The incremental
       zone transfer will contain the changes made to the zone since the
       serial number in the zone's SOA record was N.

       Reverse lookups - mapping addresses to names - are simplified by the -x
       option.  addr is an IPv4 address in dotted-decimal notation, or a
       colon-delimited IPv6 address. When this option is used, there is no
       need to provide the name, class and type arguments.  dig automatically
       performs a lookup for a name like 11.12.13.10.in-addr.arpa and sets the
       query type and class to PTR and IN respectively. By default, IPv6
       addresses are looked up using nibble format under the IP6.ARPA domain.
       To use the older RFC1886 method using the IP6.INT domain specify the -i
       option. Bit string labels (RFC2874) are now experimental and are not
       attempted.

       To sign the DNS queries sent by dig and their responses using
       transaction signatures (TSIG), specify a TSIG key file using the -k
       option. You can also specify the TSIG key itself on the command line
       using the -y option; name is the name of the TSIG key and key is the
       actual key. The key is a base-64 encoded string, typically generated by
       dnssec-keygen(8). Caution should be taken when using the -y option on
       multi-user systems as the key can be visible in the output from ps(1 )
       or in the shell's history file. When using TSIG authentication with
       dig, the name server that is queried needs to know the key and
       algorithm that is being used. In BIND, this is done by providing
       appropriate key and server statements in named.conf.

QUERY OPTIONS
       dig provides a number of query options which affect the way in which
       lookups are made and the results displayed. Some of these set or reset
       flag bits in the query header, some determine which sections of the
       answer get printed, and others determine the timeout and retry
       strategies.

       Each query option is identified by a keyword preceded by a plus sign
       (+). Some keywords set or reset an option. These may be preceded by the
       string no to negate the meaning of that keyword. Other keywords assign
       values to options like the timeout interval. They have the form
       +keyword=value. The query options are:

       +[no]tcp
          Use [do not use] TCP when querying name servers. The default
          behaviour is to use UDP unless an AXFR or IXFR query is requested,
          in which case a TCP connection is used.

       +[no]vc
          Use [do not use] TCP when querying name servers. This alternate
          syntax to +[no]tcp is provided for backwards compatibility. The "vc"
          stands for "virtual circuit".

       +[no]ignore
          Ignore truncation in UDP responses instead of retrying with TCP. By
          default, TCP retries are performed.

       +domain=somename
          Set the search list to contain the single domain somename, as if
          specified in a domain directive in /etc/resolv.conf, and enable
          search list processing as if the +search option were given.

       +[no]search
          Use [do not use] the search list defined by the searchlist or domain
          directive in resolv.conf (if any). The search list is not used by
          default.

       +[no]defname
          Deprecated, treated as a synonym for +[no]search

       +[no]aaonly
          Sets the "aa" flag in the query.

       +[no]aaflag
          A synonym for +[no]aaonly.

       +[no]adflag
          Set [do not set] the AD (authentic data) bit in the query. The AD
          bit currently has a standard meaning only in responses, not in
          queries, but the ability to set the bit in the query is provided for
          completeness.

       +[no]cdflag
          Set [do not set] the CD (checking disabled) bit in the query. This
          requests the server to not perform DNSSEC validation of responses.

       +[no]cl
          Display [do not display] the CLASS when printing the record.

       +[no]ttlid
          Display [do not display] the TTL when printing the record.

       +[no]recurse
          Toggle the setting of the RD (recursion desired) bit in the query.
          This bit is set by default, which means dig normally sends recursive
          queries. Recursion is automatically disabled when the +nssearch or
          +trace query options are used.

       +[no]nssearch
          When this option is set, dig attempts to find the authoritative name
          servers for the zone containing the name being looked up and display
          the SOA record that each name server has for the zone.

       +[no]trace
          Toggle tracing of the delegation path from the root name servers for
          the name being looked up. Tracing is disabled by default. When
          tracing is enabled, dig makes iterative queries to resolve the name
          being looked up. It will follow referrals from the root servers,
          showing the answer from each server that was used to resolve the
          lookup.

       +[no]cmd
          toggles the printing of the initial comment in the output
          identifying the version of dig and the query options that have been
          applied. This comment is printed by default.

       +[no]short
          Provide a terse answer. The default is to print the answer in a
          verbose form.

       +[no]identify
          Show [or do not show] the IP address and port number that supplied
          the answer when the +short option is enabled. If short form answers
          are requested, the default is not to show the source address and
          port number of the server that provided the answer.

       +[no]comments
          Toggle the display of comment lines in the output. The default is to
          print comments.

       +[no]stats
          This query option toggles the printing of statistics: when the query
          was made, the size of the reply and so on. The default behaviour is
          to print the query statistics.

       +[no]qr
          Print [do not print] the query as it is sent. By default, the query
          is not printed.

       +[no]question
          Print [do not print] the question section of a query when an answer
          is returned. The default is to print the question section as a
          comment.

       +[no]answer
          Display [do not display] the answer section of a reply. The default
          is to display it.

       +[no]authority
          Display [do not display] the authority section of a reply. The
          default is to display it.

       +[no]additional
          Display [do not display] the additional section of a reply. The
          default is to display it.

       +[no]all
          Set or clear all display flags.

       +time=T
          Sets the timeout for a query to T seconds. The default time out is 5
          seconds. An attempt to set T to less than 1 will result in a query
          timeout of 1 second being applied.

       +tries=T
          Sets the number of times to try UDP queries to server to T instead
          of the default, 3. If T is less than or equal to zero, the number of
          tries is silently rounded up to 1.

       +retry=T
          Sets the number of times to retry UDP queries to server to T instead
          of the default, 2. Unlike +tries, this does not include the initial
          query.

       +ndots=D
          Set the number of dots that have to appear in name to D for it to be
          considered absolute. The default value is that defined using the
          ndots statement in /etc/resolv.conf, or 1 if no ndots statement is
          present. Names with fewer dots are interpreted as relative names and
          will be searched for in the domains listed in the search or domain
          directive in /etc/resolv.conf.

       +bufsize=B
          Set the UDP message buffer size advertised using EDNS0 to B bytes.
          The maximum and minimum sizes of this buffer are 65535 and 0
          respectively. Values outside this range are rounded up or down
          appropriately.

       +[no]multiline
          Print records like the SOA records in a verbose multi-line format
          with human-readable comments. The default is to print each record on
          a single line, to facilitate machine parsing of the dig output.

       +[no]fail
          Do not try the next server if you receive a SERVFAIL. The default is
          to not try the next server which is the reverse of normal stub
          resolver behaviour.

       +[no]besteffort
          Attempt to display the contents of messages which are malformed. The
          default is to not display malformed answers.

       +[no]dnssec
          Requests DNSSEC records be sent by setting the DNSSEC OK bit (DO) in
          the OPT record in the additional section of the query.

       +[no]sigchase
          Chase DNSSEC signature chains. Requires dig be compiled with
          -DDIG_SIGCHASE.

       +trusted-key=####
          Specifies a file containing trusted keys to be used with +sigchase.
          Each DNSKEY record must be on its own line.

          If not specified dig will look for /etc/trusted-key.key then
          trusted-key.key in the current directory.

          Requires dig be compiled with -DDIG_SIGCHASE.

       +[no]topdown
          When chasing DNSSEC signature chains perform a top down validation.
          Requires dig be compiled with -DDIG_SIGCHASE.

MULTIPLE QUERIES
       The BIND 9 implementation of dig supports specifying multiple queries
       on the command line (in addition to supporting the -f batch file
       option). Each of those queries can be supplied with its own set of
       flags, options and query options.

       In this case, each query argument represent an individual query in the
       command-line syntax described above. Each consists of any of the
       standard options and flags, the name to be looked up, an optional query
       type and class and any query options that should be applied to that
       query.

       A global set of query options, which should be applied to all queries,
       can also be supplied. These global query options must precede the first
       tuple of name, class, type, options, flags, and query options supplied
       on the command line. Any global query options (except the +[no]cmd
       option) can be overridden by a query-specific set of query options. For
       example:

          dig +qr www.isc.org any -x 127.0.0.1 isc.org ns +noqr

       shows how dig could be used from the command line to make three
       lookups: an ANY query for www.isc.org, a reverse lookup of 127.0.0.1
       and a query for the NS records of isc.org. A global query option of +qr
       is applied, so that dig shows the initial query it made for each
       lookup. The final query has a local query option of +noqr which means
       that dig will not print the initial query when it looks up the NS
       records for isc.org.

FILES
       /etc/resolv.conf

       ${HOME}/.digrc

SEE ALSO
       host(1), named(8), dnssec-keygen(8), RFC1035.

BUGS
       There are probably too many query options.

COPYRIGHT
       Copyright (C) 2004, 2005 Internet Systems Consortium, Inc. ("ISC")

BIND9                            Jun 30, 2000                           DIG(1)

NAME | SYNOPSIS | DESCRIPTION | SIMPLE USAGE | OPTIONS | QUERY OPTIONS | MULTIPLE QUERIES | FILES | SEE ALSO | BUGS | COPYRIGHT

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